Temperature dependence of K(+)-channel properties in human T lymphocytes.
We have used whole-cell patch clamp to determine the temperature dependence of the conductance and gating kinetics of the voltage-gated potassium channel in quiescent, human peripheral blood T lymphocytes. Threshold for activation, steady-state inactivation, and the reversal potential are the same at 22 degrees and 37 degrees C. However, the time-constants for activation, inactivation, deactivation, and release from inactivation are quite sensitive to temperature, changing by at least a factor of five in each case over this range of temperatures. The onset of cumulative inactivation at 22 degrees and 37 degrees C reflects the time-course of deactivation. Peak outward current is approximately twofold greater at 37 degrees C than at 22 degrees C; this increase is also manifest at the single channel level. Energies of activation for conductance, activation, inactivation, deactivation, and release from inactivation are 8.2, 22.1, 25.0, 36.2, and 42.2 kcal/mol, respectively. No new channels were observed at 37 degrees C, and there was no evidence for alteration of the K+ conductance by putative modulators at 22 or 37 degrees C.
Lee
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Department of Physiology, University of Pennsylvania, Philadelphia 19104-6085.
Deutsch
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D002478:Cells, Cultured; D004553:Electric Conductivity; D004594:Electrophysiology / Q000379:methods; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008564:Membrane Potentials; D015221:Potassium Channels / Q000502:physiology*; D013601:T-Lymphocytes / Q000502:physiology*; D013696:Temperature; D013997:Time Factors
D015221:Potassium Channels